Larynx masks are supplied with supraglottic tubes which are inserted into the pharynx of a patient to keep the airways open and to ventilate the patient. By means of the supraglottic tube a larynx mask is inserted through the middle of the pharynx via the epiglottis into the lower pharynx and positioned behind or around the larynx. Such larynx masks are used to ventilate a patient while he/she is anaesthetised. They also allow the introduction of tubes, probes, optical instruments and other instruments into the airways. More and more frequently such larynx masks have oesophageal access. This allows the introduction of probes into the oesophagus and the stomach in order to remove gastric juices and other fluids as well as air from the stomach. In anaesthetised patients emptying of the stomach is intended to prevent the stomach contents flowing back into the upper respiratory tract and being aspirated into the unprotected airways (windpipe, bronchi and lungs). A further advantage of an oesophageal access is the removal of passively or actively regurgitated stomach contents from the upper oesophagus to outside, which thereby represents limited, and thus inadequate, aspiration protection. However, these larynx masks do not allow the removal of fluids from the pharynx.
A large number of different larynx masks are known on the market. A typical example is set out in U.S. Pat. No. 5,878,745. This shows a gastro-laryngeal mask in which the supraglottic tube is a pipe through which several tubes can be fed. These tubes have lumens which are used for ventilation and for an oesophageal access.
Inserting a larynx mask is not always easy. Larynx marks with a relatively rigid supraglottic tube can be introduced more easily, whereby their rigidity prevents adaptation of the position of the larynx mask to the anatomical conditions. Insertion into the pharyngeal cavity by means of a relatively rigid supraglottic tube can result in injury, and positioning in the pharyngeal cavity is not always reliable.
Highly flexible larynx masks with corresponding highly flexible supraglottic tubes allow better positioning in the larynx but are more difficult and therefore occasionally more traumatic to insert and more difficult to position in the pharynx. Accordingly, it often happens that when inserting such highly flexible larynx masks the distal end of the larynx mask, known as the tip, is bent over. This means that reliable sealing of the larynx mask is no longer present. To remedy this problem a more rigid material can be resorted to, whereby, however, the advantages of the highly flexible materials are lost. The result is traumatic effects in the central pharyngeal cavity. Even with a slightly increased air pressure in the cuff this problem cannot always reliably be solved. In the larynx masks known today, the oesophageal passage always passes through the cuff. This complicates the entire manufacturing of the larynx mask. If kinking or even just slightly greater bending of the tip of the larynx mask occurs the oesophageal passage is mostly then no longer free and an instrument or a tube can no longer be passed through.
A number of larynx masks with an oesophageal passage are known. The oesophageal passage ends in an oesophageal outlet on the extreme distal end of the larynx mask. The oesophageal passage now has to pass through the circumferential sealing area of the larynx mask. If a larynx mask is a version without an inflatable cuff, as set out in documents EP 1 875 937 or GB 2 404 863, this is relatively unproblematic as the larynx mask is overall designed much more rigidly and in practice kinking of the tip does not constitute a relevant problem.
Considerably more complex is the situation in the case of larynx masks with an inflatable cuff. On the one hand due to the thin wall of the cuff the tip of the larynx mask is very flexible and therefore susceptible to kinking, and on the other hand passing the oesophageal passage through the cuff is very problematic. This problem of passing through the cuff is solved by WO 2006/125 986 with a complex four-part larynx mask and a separate tube as the oesophageal passage which can subsequently be pushed through the cover plate and the tracheal tube.
A similar design in disclosed in US 2004/0020491. Additionally here the passed through separate tube of the oesophageal passage is sealed with a separate cuff.
Although the solution with a separate tube as the oesophageal passage reinforces the larynx mask overall, so that the risk of kinking of the tip is reduced, it makes the entire design larger and less manageable. This also applies to the solution in accordance with U.S. Pat. No. 5,878,745.
Finally a larynx mask is known from US 2003/0037790 with an inflatable cuff whereby where the closed oesophageal passage is passed enclosed over the cuff and the outlet lies at the proximal end of the tip on the other side of the inflatable cuff. The closed course, with multiple bends, makes use of the oesophageal passage for instrumentation practically impossible.